This invention relates to a disc recording and/or reproducing apparatus employing, as a recording medium, a disc cartridge housing a disc operating as an information signal recording medium, such as a magnetic disc. More particularly, it relates to a disc recording and/or reproducing apparatus having a disc rotating driving unit including a rotary shaft provided at the center of rotation and a driving pin provided at a position offset with respect to this rotary shaft for positioning and rotationally driving the disc.
Up to now, a disc recording and/or reproducing apparatus, in which a disc cartridge housing therein a magnetic disc comprising a thin film-shaped disc substrate as a signal recording layer, has been in use.
The disc cartridge, used for this disc recording and/or reproducing apparatus, is loaded on a main body portion of the apparatus as the magnetic disc is housed therein. The magnetic disc, housed in the disc cartridge, is loaded on disc table of a disc rotating driving unit provided on the recording and/or reproducing apparatus. The magnetic disc loaded on the disc table is run in rotation in unison with the disc table and has its signal recording region scanned by a magnetic head provided on the recording and/or reproducing apparatus to record and/or reproduce information signals.
If, in the above-described disc recording and/or reproducing apparatus, employing the magnetic disc as the recording medium, the information signals are to be recorded and/or reproduced correctly, it is necessary that the magnetic disc rotationally driven as it is correctly positioned on the disc table is scanned by the magnetic head to enable the recording track cut on the magnetic disc to correctly scan the recording track having information signals recorded thereon.
So, the magnetic disc and the disc rotating driving unit for loading the magnetic disc thereon are provided with a mechanism for correctly positioning the magnetic disc and for loading it in position on the disc table.
The mechanism for positioning and rotationally driving the magnetic disc is provided with a driving pin at an offset position from the rotary shaft of the disc rotating driving unit and with a metallic hub having a rotary shaft inserting opening engaged by a rotary shaft of the disc rotating driving unit and a driving pin engagement opening engaged by a driving pin.
The disc table of the disc rotating driving unit has a magnet for magnetically attracting a hub at the center portion of the magnetic disc.
When inserted into the disc recording and/or reproducing apparatus, the disc cartridge, having housed therein the magnetic disc carrying a hub having in turn the rotary shaft inserting opening and the driving pin engagement opening, is loaded in position on a cartridge loading unit provided in the recording and/or reproducing apparatus. When the disc cartridge is loaded in the cartridge loading unit, the magnetic disc housed in the disc cartridge is set on the disc table of the disc rotating driving unit as the disc hub is attracted by the magnet. At this time, the rotary shaft of the disc rotating driving unit is inserted at least into the rotary shaft inserting opening of the disc hub.
When a spindle motor of the disc rotating driving unit is run in rotation, the disc table is run in rotation prior to rotation of the magnetic disc, with the driving pin engaging in the driving pin engagement opening of the disc hub. When the disc table is further run in rotation, the driving pin is abutted against the outer peripheral surface of the rotary shaft to set the rotating position of the magnetic disc so that the disc will be rotated about the rotary shaft as the center of rotation.
In the disc rotating driving unit in which magnetic disc is run in rotation as it is positioned relative to the disc table by having the rotary shaft and the driving pin engaged with the disc hub, it is necessary for the rotary shaft and the driving pin to be reliably introduced into and engaged with the rotary shaft inserting opening and the driving pin engagement opening, provided in the disc hub, respectively.
Meanwhile, in certain disc recording and/or reproducing apparatus, employing the disc cartridge, a disc loading mechanism is used to load the disc cartridge. In this disc loading mechanism, the disc cartridge inserted into the main body portion of the recording and/or reproducing apparatus is moved in the horizontal direction perpendicular to the rotary shaft of the disc rotating driving unit and in the vertical direction parallel thereto for loading the magnetic disc housed in the disc cartridge on the disc table.
If, in such disc loading mechanism, the magnetic disc is to be unloaded, the disc cartridge is moved in the vertical direction away from the disc table and then in the horizontal direction so that a portion of the disc cartridge is placed at an insertion/ejection position. The disc cartridge, having its portion projected into a cartridge insertion/ejection opening, is again pushed into the main body portion of the apparatus to effect loading of moving the disc cartridge in the horizontal and vertical directions to enable loading of the magnetic disc onto the disc table.
The disc cartridge loaded on the disc recording and/or reproducing apparatus is ejected after the disc rotating driving unit is halted. At this time, the magnetic disc housed in the disc rotating driving unit is in such a state in which the rotary shaft and the driving pin of the disc rotating driving unit in the halted state are engaged in the rotary shaft inserting opening and in the driving pin engagement opening, respectively. If, in this state, the disc cartridge ejection operation is performed, the disc cartridge is ejected as the relative position between the rotary shaft and the driving pin on one hand and the rotary shaft inserting opening and the driving pin engagement opening on the other hand is substantially the same as that in loading.
If the disc cartridge once ejected and partially protruded via the cartridge insertion/ejection opening is again pushed into the inside of the apparatus by way of loading, such a state is obtained in which the rotary shaft and the driving pin are engaged in the rotary shaft inserting opening and the driving pin engagement opening, respectively, without accompanying disc table rotation.
However, during the ejection operation of the disc cartridge, the magnetic disc may be rotated only slightly within the disc cartridge, such that the relative position between the rotary shaft and the driving pin on one hand and the rotary shaft inserting opening and the driving pin engagement opening on the other hand is deviated even only slightly. For example, a portion of the driving pin may be overlapped with the rim of the rectangular driving pin engagement opening. If, under such condition, the disc cartridge in the ejected state is again pushed into the main body portion of the apparatus by way of loading, the disc may be loaded on the disc table in such a state in which the magnetic disc be loaded on the disc table as the distal end of the driving pin simply abuts on the rim of the driving pin engagement opening without being completely engaged therein. If, in such state, the disc table is run in rotation, the disc table starts to be rotated along with the magnetic disc, without the distal end of the driving pin being completely engaged in the driving pin engagement opening, such that the magnetic disc cannot be positioned correctly to enable correct recording and/or reproduction of information signals.
The reason of occurrence of this condition is the roughening of the rim of the driving pin engagement opening due to repeated loading and to machining error.
It is therefore an object of the present invention to provide a disc recording and/or reproducing apparatus in which the above-mentioned problem is eliminated and in which, if the disc cartridge is once ejected and re-loaded without being taken from the disc recording and/or reproducing apparatus, the disc can be positively positioned reliably in the disc rotating driving unit and run in this state into rotation.
In one aspect, the present invention provides a recording and/or reproducing apparatus for a disc-shaped recording medium having a rotary shaft and a driving pin provided at an offset position relative to this driving shaft, the rotary shaft being passed through a rotary shaft inserting opening formed in the disc-shaped recording medium and the driving pin being engaged in a driving pin engagement opening bored in the disc-shaped recording medium to set the rotational position of the disc-shaped recording medium run in rotation to record and/or reproduce information signals, wherein the disc rotating driving unit is driven to displace the driving pin from a position in which the rotary shaft inserting opening and the driving pin engagement opening in the disc-shaped recording medium are disengaged from the rotary shaft and the driving pin, respectively, at a timing when the rotary shaft and the driving pin are not engaged in the rotary shaft inserting opening and the driving pin engagement opening in the disc-shaped recording medium, respectively.
In another aspect, the present invention provides a recording and/or reproducing apparatus for a disc-shaped recording medium adapted for recording and/or reproducing information signals for a disc-shaped recording medium housed in a disc cartridge loaded on the recording and/or reproducing apparatus, the disc-shaped recording medium having a rotary shaft inserting opening at its center and a driving pin engagement opening at a position offset from the rotary shaft inserting opening, wherein the recording and/or reproducing apparatus includes a disc rotating driving unit having a rotary shaft inserted into the rotary shaft inserting opening bored in the disc-shaped recording medium and a driving pin provided at a position offset from the rotary shaft and adapted for being engaged in the driving pin engagement opening bored in the disc-shaped recording medium, and a detection switch for detecting a state of separation of the disc cartridge from the cartridge loading portion in a main body portion of the recording and/or reproducing apparatus. The disc rotating driving unit is driven to displace the driving pin when the separation of the disc cartridge from the cartridge loading portion is detected by the detection switch.
In yet another aspect, the present invention provides a disc recording and/or reproducing apparatus adapted for recording and/or reproducing information signals for a disc-shaped recording medium housed in a disc cartridge loaded on the recording and/or reproducing apparatus, the disc-shaped recording medium having a rotary shaft inserting opening at its center and a driving pin engagement opening at a position offset from the rotary shaft inserting opening, wherein the recording and/or reproducing apparatus includes a disc rotating driving unit having a rotary shaft inserted into the rotary shaft inserting opening bored in the disc-shaped recording medium and a driving pin provided at a position offset from the rotary shaft and a adapted for being engaged in the driving pin engagement opening bored in the disc-shaped recording medium, and a detection switch for detecting a state of insertion of the disc cartridge into the cartridge loading portion in a main body portion of the recording and/or reproducing apparatus. The disc rotating driving unit is driven to displace the driving pin when the insertion of the disc cartridge into the cartridge loading portion is detected by the detection switch.
Preferably, the driving pin is rotated within a range approximately 30 to 180 about the rotary shaft as the center of rotation to shift its position.
Preferably, the rotary shaft inserting opening and the driving pin engagement opening are bored in a hub mounted centrally of the disc-shaped recording medium.
Preferably, the hub is formed of a magnetic material, and a magnet for magnetically attracting the hub is provided on the disc rotating driving unit. The magnetic disc is loaded on the disc rotating driving unit by the hub being attracted by the magnet.